Currently, display screens of many terminal devices have problems, such as light leakage, liquid invasion and so forth, while most of the current display screens have a structure in which a high-temperature resistant polyester film adheres to an edge of the display screen or an edge of a side frame, to achieve the shading and waterproof effect by using a high-temperature resistant polyester film. However, as more and more terminal devices are subject to narrow border requirement currently, the black border in the display region of the terminal device is becoming narrower and narrower, resulting in a reduction in the width of the high-temperature resistant polyester film. Moreover, since when the high-temperature resistant polyester film adheres to the display screen, the high-temperature resistant polyester film is required to be beyond the edge of the display screen and have a sufficient width so as to prevent defects such as bubbles or gaps from appearing at the edge of the display screen. As the border of the display screen assembly is becoming narrower and narrower, the width of the high-temperature resistant polyester film decreases, so that light-leakage prevention effect and waterproof effect cannot be achieved by using the high-temperature resistant polyester film.